748 



ASILIDiE 



LEPTOGASTRINiE. 



Fig. iOl.—Leptogaster guttiventris (J. x 5i. 



Marginal cell open. Claws remarkably elongate, but the pulvilli 

 absent. Alula and hind-angle of the wing absent. 



Very elongate slender flies, which have the hind legs especi- 

 ally long and the hind femora and tibiae more or less clavate. 

 Pubescence and bristles almost absent, there being only one 

 preesutural and one * supra-alar bristle on the thorax. 



The character of the open marginal cell distinguishes this subfamily 

 from all the other Asilidce except the Dasypogonince, but from them it has 

 not yet been sharply differentiated. No doubts can arise about our 

 British species, and I have dealt at some length with the distinctive 

 characters of the Leptogastrince in my remarks upon the characters of the 

 Ddsypogonince on p. 705. The almost total absence of pubescence and 

 the extreme degradation of the alula and hind-angle of the wing seem to 

 point the way from the Asilidce to the Empidm. 



Face narrow near the antennae but widening downwards, bare except for a 

 mouth-beard composed of a few bristly hairs which overhang the mouth ; frons 

 narrow near the antennae bat widening upwards. Palpi one-jointed. Antennoe 

 (fig. 402) with the third joint narrowly elongate oval and with a long rather thick 

 terminal style, which is not so long as the third antennal joint. 



Thorax almost bare of bristles except for one strong praesutural bristle and one 

 strong bristle which I believe represents the last of the supra-alar bristles,* though 



* In a female L. guttiventris taken at Orford in Suffolk on July 10, HiOS, two supra-alar bristles placed close 

 together occur on one side only. 



